1. Field of the Invention
The present invention relates to a hydraulic brake device for use in restricting the rotations of wheels such as, preferably, road wheels for motor vehicles.
2. Discussion of the Related Art
Heretofore, there has been known a hydraulic brake device shown in FIGS. 9 to 12. The known device is composed of plural brakes BK (one only shown for brevity) for respectively restricting the rotations of road wheels WL, a master cylinder 2 for supplying pressurized fluid to the brakes BK when a brake pedal 1 is stepped on, an accumulator 3 for supplying high pressure brake fluid to assist the master cylinder 2 in generating the pressurized fluid, a reservoir tank 4 storing the brake fluid supplied to the master cylinder 2 and the accumulator 3, a pump unit 5 for feeding pressurized fluid to the accumulator 3, a solenoid block 6 provided with plural solenoid valves 6a therein which distribute the pressurized fluid to the brakes BK, and an ECU (Electronic Control Unit) provided with a control board 7a for controlling the open/shut operations of the solenoid valves 6a to distribute the pressurized fluid to the brakes BK and a case 7b for containing the control board 7a therein. (Reference: “Toyota Landcruiser® 100 Repair Manual”, Service Dept., Toyota Motor Corporation, Jan. 19, 1998, BR-2, BR-53, BR-54, BR-55) As shown in FIGS. 11 and 12, the solenoid block 6 is bodily mounted on a mounting portion 2a formed on the master cylinder 2, and the case 7b is secured to the solenoid block 6 by means of screw bolts 8 from the outside of the case 7b. 
Another hydraulic brake device of the type shown in FIG. 13 has also been known. This known device is composed of a master cylinder 12 of the vacuum booster type for supplying pressurized fluid to brakes BK which respectively restrict the rotations of road wheels WL when a brake pedal 11 is stepped on, a block 14 incorporating a hydraulic pump 14a therein which is driven by an electric motor 13 for generating pressurized fluid supplied to the brakes BK independently of the master cylinder 12 and also incorporating plural solenoid valves 14b which respectively distribute the pressurized fluid to the brakes BK, and an ECU 15 provided with a control board 15a for controlling the open/shut operations of the solenoid valves 14b to distribute the pressurized fluid to the brakes BK and also provided with a case 15b for containing the control board 15a therein. The block 14 is composed of the pump section and the solenoid section which are integrated as one body, and the case 15b is secured to the block 14 by means of screw bolts 16 which are inserted into the block 14 from the outside of the case 15b. 
In the known device mentioned earlier, when the control board 7a was to be replaced with another, the control board 7a was separated from the solenoid block 6 by loosening the screw bolts 8. To this end, the screw bolts a had to be arranged at the exterior portions of the case 7b, in which arrangement the space for the case 7b was not used effectively as being uselessly consumed by those spaces which were retained at the exterior portions of the case 7b for the screw bolts. Further, if it was tried to secure a sufficient space within the case 7b, it naturally resulted that the case 7b and the solenoid block 6 had to be made large. Moreover, in the replacement of the control board 7a, electronic parts fixedly arranged in the solenoid block 6 were electrically disjoined from the control board 7a and again joined with a new one as replacement parts. This resulted in deteriorating the reliability in that the durability of the joining parts was decreased and that the conformity of the electronic parts with the control board 7a got worse.
Also in the known device mentioned in the latter half, when the control board 15a was to be replaced with another, the control board 15a was separated from the block 14 by loosening the screw bolts 16. Thus, the same drawbacks were brought about. That is, the screw bolts 16 had to be arranged at the exterior portions of the case 15b, in which arrangement the space for the case 15b was not used effectively as being uselessly consumed by those spaces which were retained at the exterior portions of the case 15b for the screw bolts 16. Further, if it was tried to secure a sufficient space within the case 15b, it naturally resulted that the case 15b and the solenoid block 14 had to be made large. Moreover, in the replacement of the control board 15a, electrical disjoining and rejoining were required to be done between electronic parts fixedly arranged in the block 14 and the control board 15a. This resulted in deteriorating the reliability in that the durability of the joining parts was decreased and that the conformity of the electronic parts with the control board 15a got worse,